Fuel and method of producing same



To. all whom t may concern:

, tain new and useful Improvemen Patented Feb. 27, 1923.

UNITED STATES,

PATENT OFFICE.

LIITDON W. BATES, OF MOUNT LEBANON, HEW YOBK.,

rum. AND mmnon or rnonucnvo me.

Ro'Drawmg. Original application filed August 5, 1919, Serial No.815,497. Divided and thisapplication filed April 9, 1920.

Be it known that I, LINDON W. BATES, a citizen of the United States,residing at Mount Lebanon, in the county of Columbia and State of NewYork, have invented cerl in Fuel and Methods of Producing Same, f whichthe following is a specification.

This invention pertains to a fuel as a roduet and to the process ofproducin it. ore specifically it refers to a mobile uel, which contains,liquid hydrocarbon and particles of carbonaceous substance, so treatedthat acomposite usable for atomizable fuel purposes is produced. Theproduct is designated by the term colloidal fuel and the process iscalled colloidalizing. The word colloida in these sole instances is notused in a strictly technical sense but is used to conveniently describethe product and process, owing to certain, of the fuels importantcolloid-like characteristics. This application has been made aftercomplete reduction of the product and proce$ to practice and theiradaptation to industrial requirements.

The realm of chemistry herein treated is by no means completelyexplored, but the chemical explication indicated by the present stateofknowledge is given.

In View of the well known economic and operative advantages ofatomizable over solid fuel and the high value and comparative scarcityin many places of certain refinable oils, there has long been felt thedesirability of evolving a process for combining for purposes ofeconomy, the cheaper or more plentiful sources of carbon with thoseliquid hydrocarbons in such a fashion as to admit of atomization andsimultaneous combustion of the components. The cheaper and moreplentiful sources of carbon are generally solids, such as coal andlign-ites, or are tars and pitches. Attempts have been made in the pastto make a liquid fuel of pulverized coal with oil and of tar with oil,but as oil does not ordinarily dissolve coal or tar, comparatively rapidand uncontrolled separation, settling out or sedimentation of some ofthe components, or complications or cost of the combinat'on treatmentdeveloped, has heretofore iscouraged industrial use of the prod ct.Fortunately in colloidal fuel the sciences of Serial No. 372,686. I

chemistry and physics have at last been made to disclose a satisfactory,cheap and easy way to produce the desired fuel. Even more has been done,as a whole new range of atomizable fuels has been created.

It is a natural characteristic of solutions, whether the molecules ofthe particles or droplets actually combine or do not combine with thoseof the medium, that the dispersed particles or droplets do not settle tothe bottom, float to the top or separate under normal conditions. withrespect to colloids rovided the particles or droplets are sufficientlywithin the upper limit of the colloidal state. The requisite marginWithin the upper. limit-depends upon the real and apparent specificsuspension state, weight and size of dispersed particles and dropletsare important actors. There may be a tendency for .the particles ordroplets to float to the top rather than to settle to the bottom. Theword suspension as applied to the state of matter, does not by any meansimply stability.

In order for a fuel to be atomizable and for its components to besimultaneously combustible, it is necessary that the fuel be mobile andthat it enjoy adequate stability to enable it to pass through the pipes,preheater and other apparatus parts without the components congestingthereinto such an amount as to prevent the fuels passage. The degree andduration of the adequate stability desired vary according to thecontemplated handling and use of the fuel.

delay settling -to the bottom of t e medium such adequate or relativestability is meant.

Regulation and control, within reasonable limits, of the movement of thedispersed substance to give the fuel a stability of the required degreeand duration is sufficient for the practical purposes of fuelutilization. In order to understand how such power over stability may beobtained and exercised it is in order to describe the laws governing themovement of dispersed particles and droplets in a liquid medium. I

An investigation of stability 15 best approached from a consideration ofStokes law for the terminal velocity of fall of a spherical body in aliquid. According to this law the velocity per second under a constantforce such as gravity is derived from the following equation:

In this expression 9 is the constant of acceleration per unit'mass, thatis, gravity; 0* is the radius of the sphere; s is the specific gravityof the sphere and s that of the liquid; '1 is the absolute viscositycoeflicient of the liquid. It is obvious, as stated by Hatschek, thatthe difference (ss) may be positive, zero or negative, that is thepart1- cles may sink, remain stationary or rise, 1f their specificgravity is greater, equal to, or smaller than that of the liquid.

Droplets of one liquid in another liquid with which the first isimmiscible or partially miscible only, disclose somewhat similarstability characteristics. There are, however, lesser deviations fromStokes law as the droplets are nearly spherical, unless the volume ofthe disperse phase exceeds 74% of that of the total liquid. Liquiddispersed droplets are stable in a liquid medium when they are ofmolecular size or when the are sufliciently within colloidal limits.

lthough the actual natural rate of settling of particles and dropletscorresponding to slzes of the screens mentioned in a medium of liquidhydrocarbon is less than the theoretical, itis too rapid to allow thecomposite to be used as fuel save in very exceptional cases. In ordinarycombinations, for example, of pulverized coal and oil, the particles ofcoal being heavier than the oil have settled out in the pipes orpreheater and have choked these conduits or they have settled to thebottom of the storage tank, somewhat in the fashion of sand in water,which has defeated the purpose of simultamemos neous combustion of thecomponents ofthe fuel. There has been a similar experience in the caseof tar combined with oil. Resort to constant stirring has been proposedand tried, but even in the case of a short-pipe system congestion in thepipes it is understood has occurred. No product adequately colloidspossess the property of preventing.

such precipitation, unless a larger amount of precipitating agent isused. 0f protective colloids there are a number enumerated in standardchemistry text books. The list includes such substances as gelatine,glues, casein, gum arabic, sodium oleate. dextrin, silicic acid, andaged stannic acid. Chemists are not agreed whether the action of aprotective colloid is to surround the particles with a film, to adsorbwith them, or to introduce electrical fac tors, with resultant effectson surface tension, apparent specific gravity and other characteristicsaffecting stability. Probably the stabilizing elfect is produced by acombination of these and other phenomena.

With regard to suspending carbonaceous particles in liquid hydrocarbonit is known that less than 1% of Acheson graphite, of

2.1 specific gravity, reduced so that the dimension of the particles is75pm which is within colloidal limits, is suspended in oil forlubricating purposes with the aid of gallotannic acid; Colloids ofcharcoal and lampback are known. It is reported that coal may be ,madeinto a stable combustible colloid with oil, or brought into a stateclosely approximating the colloidal condition, when it is reducedtherein under high pressure or high speed disk grinding and lengthytrituration, whose duration may be reduced somewhat by adding a colloidto the mixture which assists the endeavor tov decompose the coal tomolecules.

Turning to the state of the art with respect to stabilizing a compositeof two or more immiscible or partially miscible liquid hydrocarbons forfuel purposes, there is little history. It is well known that manyliquid hydrocarbons are miscible with others. But there are certainimportant combustible liquid hydrocarbons that have until now provedrefractory to. combining,for instance, fuel oil and tar have been todate immiscible or partially miscible only. Emulsions of immisciblehydrocarbons have been made suitable for creosoting and disinfecting,but no such emulsions, much less suspensions, involving immiscibleliquid hydrocarbons forfuel purposes are recorded; 3 Y

One may now describe the scientific bases of thepresent product andprocess. Reduction of the carbonaceous substance to such a size that theparticles enter into amolecular, colloidal,'or practically colloidalstate with the liquid hydrocarbon i's-known to promote naturalstability. But the manner of so doing is most arduous, The question,however, of diffusion or scattering of the particles through the liquidis also of importance with reference to stability. It has been found asthe result of extensive tests that if the components are properly mixedit is not necessary so finely'to reduce the particles. The scientificreason is that the size and weight of-the particles are not the onlyfactors involved. Initial separation of the particles from each other,adsorption, electrical repulsions, and other mentioned factors havelikewises a considerable influence. These are called into operative playin a homogeneous composite.

Certain substances it is found, may be used to induce stability of asuspension of pulverized carbonaceous substance in liquid hydrocarbon.Of these a product containing lime and rosin is cheapest and mosteffective. Not all colloids or protective colloids will serve. Thetannin used by Acheson will not serve, as it apparently lacks suflicientprotective strength to stabilize particles above colloidal size.

phalts are peptizable by their own 'dis-' tillates. It has now beenascertained that carbonaceous substances conchoidal in fracture and soseemingly crystalloidal as coal and like carbonaceous substances, arealso peptizable by certain coal distillates' Even semi-anthracitepulverized coal is susceptible to some peptization, while bituminouscoals and lignites lend themselves readily to such treatment. There areusable as peptizing agents various products, liquid at ordinarytemperatures, derived from the destructive distillation of als. Such'distillates not only act upon ulverized'carbonaceous substancesintroduced into liquid hydrocarbons, but also upon the naturalcarbonaceous impurities, such as asphaltum and free carbons, encounteredin some oils and tars. The carbonaceous substance when peptized becomesto a certain extent spongified and cavitated, thereby reducing theapparent. specific It has been also found that particles considerablyabove 001- (Zsigmondy, The Chemistry. of

avity and hence the tendency to settle.

hile the chief function of thepeptizing agent is to pc tize theparticles, it has a .marked dissolving and stabilizing effect as well,which is an accompaniment of its peptizing action and which isparticularly noticeable at temperatures above normal. The stabilizingaction may be accounted for by the release into the medium of theresinous content of the coalor other carbonaceous substance upon itspeptization. It is of course possible and in some cases it isadvantageous, from the economic viewpoint, to introduce some lime-rosinprotective agent into the mixture as this reduces the amount ofpeptizing agent necessary to give. the desired adequate stability.

With reference to stabilizing two or more immiscible or partiallymiscible liquid hydrocarbons in each other the interesting scientificfact has been disclosed that the 1 presence of a considerable,percentage by weight of pulverized'carbonaceous substance, even wellabove colloidal limits in'size, has the effect, when the components areduly mixed, of stabilizing them. In'so doing the particles arethemselves. stabilized in the liquid. In such a composite there is noneed of either a protective agent or a peptizing agent. The ability 'ofcharcoal to take up gases, fusel oil, alcohol, dye stuffs and evensaltsof heavy metals is a well known chemical phenomenon. Substanceswhich greatly lower the surface tension of liquid against liquid areadsorbed by these. In a mixture of oil, tar and pulverized coal, forexample, the stabilization effect of thecoal and tar upon each other isto a certain extent reciprocal. That is, the coal. and the tartogetherin oil may be stabilized more readily than either alone. p

In the case of liquid colloidal fuel, after a completely liquidperiod'of some days or months the fuel tends to gel from the bottom ofthe container up. The viscosities ofthe gel or lower stratum 'and of theso-called serum or upper stratum, are different and the gel may carrysomewhat'more particles,

but the fuel retains its atomizable character, and in the case of bothstrata the several components are present. and are simultaneouslycombustible. Pumping, agitation or heat causes the gel to revert to aliquid, and in some cases this will result even from atap on the wall ofthecontainer. The creation of a gel, even in its early stages,materially assists stabilization, inasmuch as the particles and dropletscannot settle readily 'throughagel.

Whereas heretofore endeavors to combine pulverized coal and oil and. tarand oil have sought only a liquid fuel, the present process offers as aproduct not onlyv a liquid fuel, but also products between a liquid anda solid, viz.a mobile paste and a mobile gel,

all of which comply with the requirements that the. fuel be atomizableand that the components be sin'niltaneously combustible. (-olloida-lfuel in liquid form may be made containing up to about 45% by weight ofcarbonaceous particles. ll'lobile pastes may be made carrying as much as75%, more or less, of particles. Mobile gels may be made from liquids orpastes. (olloidal fuel may be a combination of these forms. In theseforms and between these. approximate ranges, a great number of liquid orother mobile fuels may be prepared.

A judicious and proper selection of the components to be made intocolloidal tuel is of great importance to the success of the operation.All classes of carlmnaceous substances. susceptible to reduction toparticles by pulverization or otherwise, are suitable for combining withliquid hydrocarbon n11- der the process of producing colloidal fuel. Forinstance, anthracite, semi-anthracite, bituminous and semi-bituminouscoals, as well as lignites and pants are usable. Anthracite culm, dustand slush, also bitumin- 011s and lignite slack, screenings and dust.

and also coal seam dust of suitable qualities are all available. To thislist may be added pressure still, smelting, and gas house cokes andcharcoals. Various grades with- -in these groups have been successfullyemployed. The type of lignite containing some 20% of water is suitable.lVoods, when suitably pulverized, may also be combined under the processwith liquid hydrocarbons. Carbonaeeous substances 'of comparatively highash and sulphur content may be used. lV hen colloidal fuel is burned,the ash in the particles of the carbonaceous substance, as a result ofpulverizing and colloidalizing, does not slag, but goes off to a largeextent with the gases and the remainder falls to the bottom of thefurnace as a fine powder, like pumice. The sulphur content may beaveraged down by combining the carbonaceous substance with liquidhydrocarbon containing less sulphur proportionately. Several kinds ofcarbonaceous substances together may be used.

Among the carbonaceous substances may be included particles which act asfillers to promote stability. These may be of less Specific gravity thanthe oil and must act as nuclei for flocculation, but by reason of theirbuoyancy operate in the opposite sense to the increased tendency tosedimentation due to flocculated groups of particles. F illers shouldhave also a faircalorific value and be readily subdivisible, Thepresence in the filler of a certain amount of water and somehygroscopicity are not a disadvantage when increasing viscosity is in-'volved. Various cellulosicand semi-cellulosic by-products are suitableas fillers, such as waste from starch, corn and flour fack-omponentpurposes.

tories, also wood pulp, wood dust, and disintegrated peat and lignite.Wood dust containing rosin would be usable simultaneo-usly forprotective, 'filler, and objective In the materials mentioned, the truedensit may be somewhat higher than that of 0]], but the apparent densityis lower by reason of occluded air which gives apparent buoyancy.

'lhe carlmnaceous substance or substances heretofore enumeratedordeseribed should be reduced by pulverizing or otherwise so that about95% passes through a 100 mesh screen and 85"., through a 200 meshscreen. Finer reduction is advantageous but is not essential to the.process. In fact even coarser particles may be temporarily and partiallystabilized, adequately for certain fuel uses. The peptizing treatmentwith its incidental dissolving and the mechanical blending do reducesomewhat further the particle size, but in colloidal fuel as producedmany particles are found well above colloidal size. ()ver peptization,in fact, creates an unstable composite. For the reduction "of thecarbomu-eous substance to the size employed, mechanical, electrical orchemical means may be used, though an ordinary coal pulverizing ball ortube mill is most economical. The Word pulverized. is deemed to embracecarbonaceous substance reduce-d to the form of particles, either beforeor during the blending process.

In general all liquid hydrocarbons which are usable as liquidcombustible, miscible or not with others, such as oils, tars, andpitches, may be used as a dispersion medium for particles ofcarbonaceous substance to form colloidal fuel. Such large amount of anyone highly viscous liquid as would destroy the atomizable character ofthe product should not be used. The product has been successfully madewith all liquid hydrocarbons tried; including fuel oils, pressure stilloil or tar, and coal tar, both by-' products of coke ovens and gashouses. By the term pressure still oil or tar is meant the residue leftafter topping and cracking a paraflin base oil in pressure stills.Liquid hydrocarbons of various classes and grades in these groups havebeen successfully utilized. Liquid hydrocarbons of even higher sulphurand water content than would ordinarily be acceptable for liquid fuelmay be used, inasmuch as it is possible on colloidalizing to averagedown these factors by using carbonaceous substance of proportionatelylower content. Solid hydrocarbons when liquefied are also utilizable,provided the liquid falls within the above mentioned groups. carbons maybe blended.

In order to carry in liquid from a highpercentage of carbonaceousparticles, the liquid hydrocarbon should have a viscosity Several liquidhydroby emulsifying the oil.

of about 20 En ler at 2O" C. and'10 Eng ler at 30 (1; A esser viscositwill not. revent the production of col oidal fue it merely tends toreduce the percentage of articles which may be introduced into i uidhydrocarbon without chan ng the.

uced petroleum, etroleum residuals and.

petroleum or aspha tic pitch. If pitch is used some 5% to 10% by weightwill raise the viscosity the desired amount. Standard Navy fuel oil, forexample, having a viscosity 7.8 Engler at 20 C. and 43 Engler at 30 C.is raised t the above mentioned figures by 12%75 of petroleum pitch.Viscosity raising liquids may be combined with the liquid hydrocarbon ofthe medium by simply blending the two in the manner that suchliquidslare ordinarily blended. Pitch may be advantageously.incorporatedin fuel oil by heating it'.with 25% to 30% of the oil at so1ne110 C. andthen stirring in. the remaining oil. Viscosity may beraised also It isone of the qualities of the protective agent thatit increases theviscosity ofv the oil. The rosin and lime in oil form an emulsoid ofviscosity increasing typel The better the quality of the protectiveagent, the more a given amount increases the viscosity. ,Viscosity atnormal temperatures may be further increased by after treatment of theemulsoid. This consists in heating and cooling it several times. Careshould be taken .not to ripen too far, as a less stable system may beformed from which the lime-rosin component tends to partially separate.

If the viscosity of the liquid hydrocarbon selected to constitute thedispersion medium is too great to. yield a liquid product in view of theamount of particles it is desired. to introduce, this quality may bereduced by blending with a liquid a cut-back consisting of othersuitable liquid hydrocarbon.

One may mention,-pressure still oil or tar, kerosene and turpentine. Incase a liquid of viscosity greater than about 40 Engler at 20 C. is tobe used, it is well for practical purposes to introduce less particlesthan the maximum'stabilizable in-a liquid form. The manner of blending.one or more cut-backs with liquid hydrocarbon is well known.

The composition of the protective agent or fixateur is of importance asit materlally affects the amount necessary to give the dereplaced byother alkali.

sired fuel stability and consistency. The 'fixateu'r ma be' prefaredinvariousforms,

v or, paste or liquid. The amounts of limeand rosin may vary withincertain limits according to the duty to be 7'0 such .asa so id, pow

performed. 1% fixateur means a lime- -rosin composite of suchan amountas will 'addi1% rosin to'the fuel. The percentages of lime and otherfixateur components are included in the colloidal fuel formulae underthe percentage assigned to a liquid 'oompo- .1

nent of the fuel.- Various grades of limercsm products may be. formed.The eflimoney. of the protective agent depends upon the purity of theingredients, their quahty, 130

and, in the case of. soap or. mass, inthe completeness of the saponication. The content of resinous acids in the rosin is an importantfactor and counts for more than lightness of color. Rosin may bereplaced 5 by balsams, 'turpentines, and other resinous, by-products.Wood pitch particularly. from pine, wood tar, and partly distilled pinewood, may also serve, provided the calorific value of the fixateur isnot decreased mate- 3 rially. A fresh and somewhat low-burnt quick limemay be used. What is known as fat lime is desirable. The lime may be maybe incorporated.

In general, with a goodquahty of protective agent, I one may regulatestability by yarylng the amount used. Broadly speaklng, the less thedegree and duration of the desired stability, the lower the temperature,g

the fewer particles introduced and the.

smaller their size, the less fixateur need be employed- The greater" theviscosity coefficlent of the liquid, the less protective agent isrequired. If fillers are used, less protectwo agent may be needed. If apeptizing agent is added to the composite or if other llquid hydrocarbonimmiscible with the dis persion medium are joined to the fuelcomponents, then less fixateur is called for.

The tendency to early, complete and consistent gel 'is promoted bysomewhat larger 1 amount. of protective agent than would be used simplyto stabilize the particles in a liquid fuel. duced less agent than if aliquid fuel is to be made may be required. Some fixateur may, however,be needed to prevent separation of a liquid to the top of the paste.

The amount of fixateur used should provide for adequate stability at thetemperatures of storage and preheater. The maximum of a good quality ofagent practically ever used is an amount which adds by weight some 2%rosin to the fuel. The minimum serve as 'peptizing agent the middlefrac- Other components If a paste fuel is to be-pro- 115 of coal isselected as a part of the dispersion medium then no further peptizer isneeded. But the entire dispersion medium should not be a peptizer if thesolids are susceptible to peptization and if the corresponding treatmentis given. In the composites including a peptizer stability does not fallofl? with rise in temperature progressively in extent as. it does withcomposites stabilized with the use of a protective agent alone. But ingeneral, the amount of peptizer varies in the same fashion as does theamount of protective agent heretofore mentioned.

In relation to stabilizing two or more immiscible liquid hydrocarbonswith the use of pulverized, carbonaceous substance the percentage ofnecessary carbonaceous particles varies with the nature and relativeamounts of liquid hydrocarbons. An adequately stable composite may bemade, for example, consisting by weight of about 507, pressure stilloil, 20% coke-oven by-product' tar, and 30% pulverized coal. If an oilsuch as that from Texas is used the proportion of coal or othercarbonaceous substance to tar has to be increased and the proportion ofcoal and tar to oil has to be decreased. If a small amount of protectiveagent is added to the mixture, the highest amount of tar may bestabilized in oil with the aid of coal or other such carbonaceousparticles.

Examples of the regulation of the duramesh screen and 95% passes a 200mesh screen. The viscosity of the fuel oil mentioned is about 20 Englerat 20 C. while that of the pressure still oil is only 8 Engler at 20 C.The specific gravity of the oil in the rst full oil example is .924,whilein the two last it is .943. That of the pressure still oil is .960.The actual specific gravity of the Pocohontas coal is 1.39, of theanthracite coal 1.6, of the coke 1.7. Stability of over ten daysattaches to a composite consisting of 40%% pressure still oil, 3%pressure still wax tailings, 15% road oils, 1 fixateur and 40%pulverized anthracite coal. Stability of over;

three months is noted in a composite" consisting of 50%;% pressurestilloil, 3% "pressure still wax tailings, 1%% fixateur, 30% pulverizedpressure still coke and 15% petroleum pitch. The combination of 67.8%Navy fuel oil, 31.2% pulverized bituminous coal and 1% fixateur isstable for over six months. Stability for over six months is also notedin the case of a composite consisting of fixateur, 3% middle fractionoil, 5(r1% pressure still oil 5% coke-oven byproduct tar, and 35%pulverized Pocohontas high volatile bituminous coal.

In colloidal fuel the amount of settling during the calculated life ofthe composite, or period of assured stability, rarely amounts to 5% ofthe particles. Usually at the end of the period stated between 95% and99%, or even 100% of the particles are still in suspense and Wellscattered through the composite. Thereafter settling begins graduallyand proceeds progremively. Temporarily renewed life may be given by stirring with or without more fixateur. The stability mentioned earlier isadequate stability in liquid form. The period of usability of the fuelmay be longer as utility is not jeopardized by such small and gradualsettlings and there -may be further life. in gel form. The stabilitymentioned is at a temperature between 20 C. and 30 C. At highertemperatures the period of stability is shorter, save in the case ofcomposites in which a peptizing agent is introduced. The

stability is of greater degree orduration' than that duetomerehighviscosity of the medium, if it is high, and persists under thepreheat necessary for atomization. Greater amounts than that required of,any mentioned agent will not of themselves, save in an extreme case,prejudice the fuels utility, While lesser amounts simply decrease thedegree and duration of stability or retard formation, lessen the extentand change the consistency of the gel. Either or both agents areembraced in the term protecting agent.

WVith reference to the apparatus needed to produce the composite, onemay say that it consists chiefly of. suitable blending mechanism.Ordinary paint mixing mills, coal pulverizing mills and other knownmechanical apparatus may be adapted to this use and serve as a unit inapparatus to make colloidal fuel. If a part of the container in whichthe components are placed is suiticientlyheated, a circulation of theliquid will. be set up which will cause the particles to scatterthroughout the mixture. If the heat is raised to between C. and 95 C.the homogeneity will become satisfactory. Heat maybe combined withmechanical agitation or blending. In casev a peptizing agent is usedthis heat blending treatment may advantageously be utilized with orwithout a mechanical treatment, and the product allowed to'rest for somehours to advance peptizationif storage is intended. When the aspha-ltumand free carbon particles .are to be stabilized one may centrifuge,

is desired, the oil initially to lessen the amount of these impuritiestostabilize.

The manner of mixing or blending the components of'colloidal fuel issimple but important. The carbonaceous substance or substances ma bepulverized simultaneously with the blen 'ng of the components, orseparately. The fixateur may be made beforehand, or its componentsunited when the fuel components are blended. Protective and peptizingagents, viscosity adjusting liquids, and fillers, or any or several ofthem, may be introduced at any time before the blending is terminated.The duration of the mixing treatment varies with the components and withthe stability desired. The introduction of new components and thewithdrawal of already mixed components may "take place simultaneously ina continuous process. In general the product is satisfactory when oninspection it is seen to have considerable and consistent smoothness tothe touch. Suitable tests to determine when blending is sufiicientinclude many known to chemists, such as gravity tests with the fuel atrest and in motion, viscosity tests, atomization tests, centrifugaltests, and dripping tests. Evenness in a drip test tends to show thatproper homogeneity has been reached. Only a few minutes total blendingtime is usually employed to give homqgeneity in apparatus of the kindmentione although if long stability is required or if the initialviscosity of the liquid component is low a greater duration of treatmentor repetition of treatment may be advantageous.

While the components of the protective agent may be added to othercomponents of colloidal fuel before or while the latter are beingblended, it is advantageous to prepare the agent beforehand, in aseparate step from the colloidalizing or on another occasion and storeit until used. The agent hereafter described is simply one form oflime-rosin product, a fixateur grease. Fixateur powder has been made.The fixateur herein given as an example is composed by weight of about83.5% Navy fuel oil, 10% rosin, 5% lime and 1.5% water. The formula isnot inflexible, as different percentages of each of the compon'ents maybe used. The above percentages, however, yield a suitable grease. Theoil used in making the fixateur should have a certain minimum viscosityand flash point. While the emulsification of lime-rosin soap is possiblein almost any fraction of mineral oil, yet the stability of the emulsiondecreases as the viscosity of the oil becomes less. Since, also, it isnecessary to heat the oil up to about 120 C.', which is above themelting should have a viscosity of about 20 En he at 20 C. and 10 Englerat 30 C. 'avy fuel oil, for example, of viscosity 18.1

Engler at 20 C. and 9.3 Engler at 30v C.

is suitable. As in the case'of oil to be used as dispersion, medium forcoal particles, the.

oilused for grease makin may be raised or lowered in viscosity to-t efigure desired. But pitch should not be used as it preventssaponification and greaseformation. The grease-making method is asfollows: 1. H drate the lime before combining it with tli e other inedients, unless the lime is obtained a ready hydrated. 2. Screen it ifnecessary. The lime'powder should mostly beable to pass a 200 meshscreen. a 3. Stir the lime with the oil heated to about 120 C. The limeis stirred in with the oil and kept in suspension by agitation while theoil is heated. The stirring should be vigorous and such as will produceproper agitation and mixin 4. Add the Water and hold the heat orsaponification. A small amount of water (1 to 5%) is necessary for aconsistent grease. I -It may be incorporated mechanically by puggingwith the cold grease, but it is better toadd it during the heating,generally just previous to adding the rosin. Sometimes another 5% to 1%may be added just before cooling the grease, if there has been much lossby evaporation. The presence of Water leads for a short time to muchpriming or foaming, so that .it is desirable-to use a mixing vessel of avolume greater than that of the material used. 5. Melt the rosin andpour it into the lime-oil mixture while this isstill hot.

The rosin may be separately heated until quite liquid. 6. Add the rosinwith con sta'nt stirring to the heated mass of lime and oil. Airagitation should be utilized with mechanical stirring or alone to givethe required mixing when the priming stage is reached. It may beadvantageouly introduced through the lowest part of the mechanicalstirrer; The use of preheated air is of value to help maintain anddistribute the heat. The water content of the reaction mixture may beheld constant by' a Fuller mill so that 97.5%

and their consistency compared with that of a sample of standard greasemade under similar conditions. Two connected processes are going onduring the heating,

namely, the chemical process of saponifica tion of the resinous acids bythe lime and the einulsification and solution of the soap in the il. Theproduct is a protective agent, lime-rosin grease, or fixteur, so-called.

The first example selected to illustrate colloidal fuel is thatcomprising a Navy fuel oil from Texas combined with pulverizedPocahontas coal. Take such a fuel oil of a viscosity of about 18.7Engler at 20 C. and 93 Engler at 30 G. Take such a coal pulverized sothat some 99.7% passes a 100 mesh screen, 98% a 200 mesh screen and 85%a 300 mesh screen. Take a grease in which lime and rosin areincorporated into fuel oil as described so thatthe grease contains byweight 83.5% fuel oil, 10% rosin, 5% lime and 1.5% water. Use as ablending apparatus an ordinary paint mix-' ing machine, whose wheelweighs about 200 lbs. Rotate the wheel at 70 R. P. M., which is slowerthan usual.- Place in the paint mill a bath of such amounts ofcomponents that there will be combined by weight 30.5% coal, 1.5%fixateur and 68% oil. Blend the mixture sim ly the time necessary forthe composite to run through the mill, which is a few minutes only, asin the case of paint mixing. The product is a colloidal fuel which isstable in liquid form for over three months.

A second example of colloidal fuel is that containing by weight:Pressure still oil 50%, coal tar 10%, creosote 2%, pulverized Pocahontascoal 30%, fixateur 1.2%, Texas Navy fuel oil 6.8%. Pulverize the coal inasses 100 mesh and 95% passes 200 mesh. Ks blending apparatus useanother ordinary Fuller 37" diameter coal pulverizing mill, in whichfour 100 lb. balls are resent. Rotate these at a speed of 135 R. M.,which is slower than the usual pulverizing speed of 150 R. P. M. Thecomponents, including the pulverized coal, are gradually fed into theblending mill in correct proportions corresponding to the ratio ofcomponents, so as to run through it for a few minutes, until a liquidproduct showing adequate homogeneity upon examination is produced. Ascomponents are suitably introduced the finished product flows out in acontinuous stream. The product is a colloidal fuel which is stable forover four months in liquid form.

' means that such colloidal fuel may be kept.

under a water seal, and when on fire the flames may be quenched in andby water.

Colloidal fuel, furthermore, enables one to give the flame-used inmetallurgical process the degree of hardness or softness desired. It iswell known that coal gives a soft flame while oil gives a hard one.In'certain steel and other metal processes the character of the flame,as distinguished from the degree of heat, is of supreme importance.Colloidal fuel gives a new ability to regulate not only the B. T. U. ofthe fuel but also the nature of the flame. All that is necessary is tomake up the composite with such amounts and kinds of components as willgive the desired heat units and a flame of the character required. Forexample, acomposite in which a high grade of carbonaceous substance isused has more B. T. U. than one made of a poor grade. A compositecontaining a high percentage of carbonaceous particles gives a softerflame than'one carrying a lesser percentage.

Liquid colloidal fuel, carrying up to 40% of carbonaceous particles, ispractically the equivalent, in regard to handling to the preheaterstage, of the heavier class of crude oil. At higher temperatures,however, such as obtain in the preheater it may approximate the behaviorof the lighter class of oils. The problem of burning colloidal fuel issimply that-of burning a viscous oil. In the case of a gel which isliquefied by pumping or which .liquefies in the .preheater,

more pressure is apparently alone required. 0

Colloidal fuel is not an'ordinary coal and oil mixtureas'it has astability feature, subject to control. It is a composite in three statesof dispersion: solution, colloid and suspension. Some of the particlespass through a filter, many do not. Many are microscopically visible andmeasurable, others are not. Some display rapid Brownian movement, othersslower, others no such movement. In colloidal fuel, a material amount,if not the bulk, of the carbonaceous particles remain in the productwhen produced greatly above the colloidal size and above the colloidborderland. In view of this condition it has become possible to dispensewith the complicated treatmentnecessary to reduce the particles tomolecular or colloidal size, a procedure more suited to the laboratorythan to industry. It may be replaced by a brief low speed blendingvtreatment under normal pressure, or by a heat treatment, forhomogenizing purposes; The nature of the best and cheapest protectiveagent has been ascertained and the method for preparing it determined.It artificially induces stability in a composite whose condition wouldnot be stable naturally. duration than that due to mere high viscosityof the medium. Furthermore, the protective agent is partially orcompletely The stability is of greater degree or replaceable in certaincases by a peptizing agent. The peptizing agent indicated has as anadditional feature certain protective and dissolving action. Theviscosity of the liquid hydrocarbon is adjusted to suit the amount andtypes of components to be used and the product desired. The product -ismade to give the B. T. U. content, the flame character and the sulphurand water content desired. Finally, immiscible or partially miscibleliquid hydrocarbons may 110W also for the first time be combined withthe aid of carbonaceous particles, into an adequately stable atomizablefuel.

No claim is made herein broadly to a stable mobile fuel consistingessentially of liquid hydrocarbon and pulverized solid car'- bonaceoussubstance and containing also a smaller proportion of an agent havingpeptizing qualities sufiicient to prevent sedimentation for apredetermined period, or to a method of producing a stable mobile fuelconsisting essentially in effecting an admixture of a relatively largequantity of liquid hydrocarbon and pulverized carbonaceous substance,and a relatively smaller quantity of an agent capable of promotingstability, and subjecting the mixture to such heat and mechanical homoen izing action. that the main portion of t e particles of thecarbonaceous substance remain above colloidal size, .whereby thecomposite is stabilized, as such matter forms the subject of myapplication 315,497, filed on or about the 5th day of August, 1919,Patent 1,390,228, of which this application is a division.

What is claimed is 1. A liquid or liquefiable mixed fuel comprising alarge proportion of hydrocarbon oil and a substantial proportion ofsolid carboniferous fuel in the form of a powder, a substantial portionofthe powder being adapted to ass a filter which will pass ordinarycolloids and a substantial portion of the powder being adapted to beretained on such a'filter, sald solid carboniferous fuel being adaptedto be burned independently as fuel, and said fuel mixture also c0mpris-;ing a medium adapted to hold said powder in suspension a' much longertime than results from the viscosity and relative specific gravity ofthe components of the mixed fuel.

2. A stable mobile atomizablefuel composed essentially of particles ofsolid carbonaceous substance in an amount which will produce a fuel ofspecific gravity reater than that of water, which substance 1sartificially ulverized in a manner which reduces material portionsthereof to molecular, colloidal and suspension sizes; a large body offreely' flowing liquid hydrocarbon;

and a smaller amount of substance which stabilizes theparticles both atnormal temperature and when the viscosity of the fuel is reduced underthe elevated temperature requisite for the fuels atomization throughburners.

3. That method of producing a stable mobile atomizable fuel, whichconsists essentially in mixing liquid hydrocarbon and particles of solidcarbonaceous substance in amounts which will produce a composite ofspecific gravity greater than that of Water without destroying theatomizable character of the composite; and colloidalizing thecomponents.

4. A stable mobile atomizable liquefiable fuel comprising solid articlesof carbonaceous substance, liqui hydrocarbon, and sa onified resinousmatter.

11 testimony whereof I have signed in name to this specification.

LINDON W. BATE S.

